American police are poring over the social media accounts of Cesar Sayoc in an effort to understand what turned an amateur bodybuilder and DJ into a liberal-baiting Twitter troll, suspected of posting mail bombs to prominent Democratic politicians and supporters.
The 56-year-old is due to appear in court on Monday to face five charges, including illegally mailing explosives, threatening a former president and assaulting federal officers.
He was arrested on Friday after a coast-to-coast manhunt that began four days earlier when a homemade bomb was found at the home of George Soros, the billionaire philanthropist.
Relatives and colleagues described an isolated, bigoted figure who made no secret of his hatred for minorities.
The discovery of devices sent to Barack Obama, Hillary Clinton, the offices of CNN, Robert de Niro and others, put the US on high alert just two weeks before midterm elections, and provoked an intense round of soul-searching about the country’s increasingly hostile politics.
Law enforcement officers said they believed Mr Sayoc was responsible for sending 14 packages so far and was identified after a fingerprint was found on one of the envelopes.
However, they warned that the threat may not be over.
Christopher Wray, director of the Federal Bureau of Investigation, said: “There may be other packages in transit now and other packages on the way.”
Mr Sayoc was arrested at a car parts shop on Friday morning. Officers towed away a white van, covered with inflammatory stickers professing support for Donald Trump, in which the suspect was believed to be living.
“Dishonest Media,” read one sticker visible in video footage. Another said “CNN Sucks” - a favourite chant at Mr Trump’s rallies - and featured crosshairs on a photograph of one of the channel’s pundits.
Before 2016, Mr Sayoc’s Facebook account (deactivated on Friday) offered little political comment. Instead, it focused on bodybuilding and promoting events where he DJed.
But his Twitter account, which was set up in April 2016, offered a stream of political consciousness, mixing threats, with pro-Trump bombast and conspiracy theories.
It included posts suggesting he attended one of Mr Trump’s campaign rallies in 2016, as well as his inauguration in January 2017 and another rally a month later.
He shared virulently anti-Muslim memes and described a survivor of this year’s Florida school shooting as a “fake phoney”. He also posted the address of Mr Soros as well as photographs of some of the homes that later received homemade bombs in the mail.
His former manager at a pizza restaurant described how he openly admitted being a “white supremacist.
Debra Gureghian said he had worked as a delivery driver in Fort Lauderdale for more than a year before quitting in January.
He had told her she should be “put on an island with all the other gay people and burned” for being a lesbian, she said.
“He was anti-gay, anti-black, anti-Jewish, you name it, everybody that really wasn’t white and wasn’t a white supremacist didn’t belong in the world, that’s what he used to say to me all the time,” she told CNN.
Mr Sayoc had also worked as a DJ at a strip club, in West Palm Beach, and reportedly as a stripper in the 1990s, according to local media reports.
Ron Lowy, his former lawyer, confirmed details of a criminal record, including arrests for fraud and drug possession.
In 2012 he was charged with threatening his local power company with an attack that “would be worse than September 11”. He was sentenced to probation after pleading guilty.
“He doesn’t seem to recognise reality,” Mr Lowy told local media organisations. “He lives in a fantasy world.”
As police continue their investigation, the political fallout is already echoing through the campaign trail.
Democrats point out that have been singled out for abuse by Mr Trump during his rallies or on Twitter.
Meanwhile, Mr Trump used an election rally to accuse the media of trying “to use the sinister actions of one individual to score political points” against him.
“The media's constant, unfair coverage, deep hostility and negative attacks ... only serve to drive people apart and to undermine healthy debate," he told 9000 cheering fans in Charlotte, North Carolina, comments that stand in contrast to his earlier calls for unity.
The criminal complaint, filed at a Florida court, says all the devices were the same. They comprised a length of PVC pipe, a small clock, wiring and “energetic material”, a technical term for materials including explosives.
Some also included photographs of the intended target marked with a red X. Each manila envelope was posted with six stamps.